Inkjet Print Position Adjustment via Clear Ink Density Contrast

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Solution Overview

Problem

Conventional techniques for printing check patterns to adjust the print position of clear ink in inkjet printing face challenges in achieving sufficient color or density differences between overlapping and non-overlapping areas, leading to inaccurate position adjustment and ejection state checking due to small changes in color or density.

Innovation Solution

The method involves printing patterns with clear ink and coloring material inks in an overlapping manner to maximize color or density changes, using specific nozzle arrangements and optical sensors to detect these changes, and adjusting print positions based on measured reflection densities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If coloring material inks are printed to overlap the clear ink in order to detect a change in color or density, then the state of ejection can be checked, but the amount of change in color or density is insufficient between overlapping and non-overlapping areas

Engineering Contradiction:
Improvedetection accuracy of clear ink ejection stateVSAvoidsufficiency of color or density difference for detection
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A background pattern is introduced as an intermediary element that enhances the optical contrast between areas with clear ink and areas without clear ink. The background pattern serves as a reference that amplifies the detectable difference when clear ink overlaps with coloring material inks, thereby improving detection accuracy without requiring large changes in the coloring material inks themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the optical parameters of the printing system by using specific combinations of clear ink and coloring material inks with complementary optical properties. By selecting inks with appropriate transparency and color characteristics, and by controlling the overlapping patterns, the system maximizes the optical density difference between overlapping and non-overlapping areas for improved detection.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If clear ink is ejected to print an HS pattern for head shading correction, then the amount of application can be adjusted, but sufficient change in density for detecting a difference in applying amount cannot be obtained

Engineering Contradiction:
Improvecorrection accuracy of applying amountVSAvoiddetectability of density difference
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The background pattern acts as an intermediary that enhances the density variation caused by different applying amounts of clear ink. When clear ink is applied over the background pattern, the optical density change is amplified, making it easier to detect and measure variations in applying amount for accurate head shading correction.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention applies different patterns and ink combinations in different local areas to optimize detection. The background pattern is strategically placed in areas where clear ink application varies, creating localized zones of enhanced contrast that allow for precise measurement of applying amount differences.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If conventional check patterns are used for adjusting print position of clear ink, then the adjustment process can be performed, but high-accuracy adjustment cannot be achieved due to small color or density changes

Engineering Contradiction:
Improveability to perform print position adjustmentVSAvoidaccuracy of print position detection
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The background pattern serves as an intermediary reference that enhances the visual and measurable contrast for print position alignment. By providing a distinct background pattern that interacts optically with the clear ink and coloring material inks, the system creates more pronounced density differences that facilitate accurate print position detection and adjustment.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances the accuracy of print position adjustment and ejection state checking by increasing the color or density differences between overlapping and non-overlapping areas, allowing for precise control and improved printing quality.

Implementation Method 1

using specific nozzle arrangements and optical sensors to detect these changes, and adjusting print positions based on measured reflection densities

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3098079B1Inkjet printing apparatus and check pattern printing method
Publication Date: 2021.01.20 CANON KK
  • EP3098079B1 patent drawingFigure 1
  • EP3098079B1 patent drawingFigure 2~3
  • EP3098079B1 patent drawingFigure 4

AI summary

There is provided an inkjet printing apparatus. The inkjet printing apparatus includes a receiving unit configured to receive an instruction to perform check processing, and a controlling unit configured to cause a printing unit to eject a first coloring material ink, a second coloring material ink, and a clear ink so as to print a check pattern used for the check processing, wherein the printing unit prints the check pattern in which the clear ink, the first coloring material ink, and the second coloring material ink are applied to a check pattern forming area of the print medium in this order, and in the check pattern, the clear ink is colored in the second color and the first color in a direction from a surface side of the print medium toward a back side of the print medium in this order.